OKLAHOMA CITY - New research is underway into understanding what happens before a tornado touches down.

Researchers are not looking in the sky like you would expect. But underground. Researchers are using seismographs to study what atmospheric activity takes place before a tornado hits.

Before a deadly tornado tore through the Midwest late last month, seismographs registered a strong, low-frequency pulse beginning around 4:45 a.m.

Geologists in Indiana say the equipment was not recording the tornado itself, but the atmospheric pressure that caused the storm.

"It's perfectly reasonable to assume that would happen," said Austin Holland, a seismologist with the Oklahoma Geological Survey.

Holland said seismic waves travel faster than the actual storm and a seismograph buried underground could register a change in atmospheric pressure miles away.

"There is a huge pressure difference differential between the center of the storm and outside of the storm and that puts a weight and decreased weight on the surface of the earth. So it's compressing the earth differently," Holland said.

Researchers are now looking closer at the data hoping to gain more knowledge about what causes tornados.

But News 9 Chief Meteorologist Gary England says we already know where the big tornados are going well before they hit.

"When a large super cell forms, it's giant low pressure area and so there's less pressure on the earth," said England. "You can have some uplift mother there that might cause some noise before there's a tornado, but using that to predict tornados, I think it's not worth the money."

Holland agrees saying radar is much more accurate and a better source of predicting a tornado.